Steel strips for band saw blades, frame saw blades as well as circular saw blades conventionally are made of a steel which provides a good swaging and/or spring setting ability in combination with high wear and fatigue resistance, which features are worthwhile for conventional band saw blades, frame saw blades and circular saw blades where the entire blade consists of a single material and the saw teeth are shaped by plastic deformation and grinding. These features of the blade, however, are not of significant importance for band-saw blades, frame saw blades, and circular saw blades of the type where the tooth tips are secured to a backing material through welding or brazing or are produced by working an edge portion which is secured to the backing material through brazing or welding. This type of band saw blades, frame saw blades, and circular saw blades are more and more common, because they offer an opportunity to use, as a material for the tooth tips, a material having a very high wear resistance, e.g. Stellite.RTM., which is a registered trademark of Stoody Deloro Stellite, Inc., Co., while the backing material consists of a strip steel. The sharpness of the tooth tips of a material having a very high wear resistance is maintained longer than if the tooth tips were made of the backing material and the time period between the regrinding operations have successively been increased. Moreover, the feeding rates have also been increased. This technology, however, raises other and ever higher demands on the backing material. This particularly concerns the backing material of band saw blades, frame saw blades, and circular saw blades for sawing in wood but also in stone and other materials. Among these demands the following should be mentioned:
a high fatigue resistance in order to be able to stand repeated bendings, varying loads, vibrations, etc; PA1 a good relaxation resistance in order to maintain the tensions which have been incorporated in the material in connection with the stretching or tensioning of the blade, i.e. that the blade does not loose its shape keeps its tension; PA1 a good brazing ability and/or weldability in order to allow the fastening of wear resistant materials on the backing material through welding or brazing and/or for joining band saw blades without impairing vital strip steel properties; PA1 a good grinding ability in order to avoid notch effects which commonly cause failures; and PA1 a good tempering resistance at the manufacturing of the blade as well as during sawing. PA1 0.01-0.1%, preferably about 0.025% aluminium and 0.005-0.05%, suitably about 0.010% nitrogen, or PA1 0.10-0.20%, suitably about 0.15% vanadium, or PA1 0.025-0.10%, suitably about 0.05% niobium, which wholly or partly can be replaced by the double amount of tantalum, or PA1 0.015-0.10%, suitably about 0.025% zirconium, which wholly or partly can be replaced by the same amount of titanium.
Besides the above mentioned demands, which the tool maker and the final user make on the material, also the steel manufacturer put some demands on the material. Thus, the steel must not be too expensive to manufacture, which i.a. implies that the steel should not contain high amounts of expensive alloying elements and also that the material should not require complicated manufacturing procedures which may be difficult to uniformly reproduce and also would cause considerable costs.